Post mounting

ABSTRACT

A yieldable assembly comprising a flange and post connected by elongated support means which allows the post to separate from the flange when struck by a vehicle but which retains connection therebetween. The support means yields under tensile strain and imparts a balanced restraining force to the vehicle after separation of the flange and post.

Posts for lighting and road signs at the side of the roads are exposedto the risk of being hit by vehicles. This relates to the roadenvironment and its influence on damage in run-off accidents, forexample. Lately, impact absorbing posts have been introduced, posts thatare sufficiently soft or which break away and thereby reduce thecollision forces that cause damage to road-users and vehicles.

It has, however, been observed that objects hit by a vehicle can damagefollowing vehicles if the object is torn loose and flung about out ofcontrol. Furthermore, a driver who has just hit a post is most often soshocked that he can hardly steer the vehicle if it continues to move on.It would, therefore, be of great advantage if the object that was hitcould relatively gently restrain the vehicle. The area of applicationcould be expanded and eventually go so far as to the placing of suchyielding and restraining posts along the central reservation of highwayswithout a need for guard rails.

The present invention is a mounting device especially suited foryielding posts, for example lamp posts, but also suited for other postslocated in the road environment.

The post mounting is in itself able to yield (either by means of shortbent supports, or supports going through the post, or by means of anenergy-absorbing attachment such as a friction attachment,) so thatforces occurring when a vehicle hits the post become as small aspossible.

Should a collision occur, the post casing becomes particularly heavilydeformed at its base. Special measures are required to ensure that thepost is not snapped off. The alternative of using a stronger design forthe post itself is unsatisfactory, as the yielding of the post to thevehicle becomes too low. By anchoring the casing in supports or similardevices that in turn can yield under balanced resistance, it is possibleto restrain both the post and the vehicle at the base of the post.

The following describes a flange mounting of the post. When hit, thecasing of the post is bent by the vehicle to a flat shape along theground, where the relatively thin shell of the casing splits and thepost becomes partly or fully loosened at its base. The pre-shapedsupports are fastened to the casing and readily follow the bending ofthe casing, but provide resistance when they are stretched lengthwise.They can therefore be designed to retain the post at its base even afterthe casing has been torn off by the vehicle.

The supports serve as an anchoring device between the foundation and thetorn-off post, with the result that both the post and the vehiclehitting it are retained.

A variation of the energy-absorbing support can be obtained by using atie plate perforated in a certain pattern. The pattern is made allowingthe plate to be torn crosswise in certain parts, not completely, but sothat untorn sections of the material retain the post at its base. Thiseffect can for example be obtained by making rows of holes across thetie plate and alternatively omitting the last hole or holes in each row,so that no rupture of the material occurs at these points. The distancebetween the edges of the holes is relatively small and the plate breaksthere when strained. A zig-zag shaped rupture pattern occurs. Byadjusting the accumulation of material, it is possible in this manner toobtain supports that moderate forces. Slots can be punched in thematerial instead of the rows of holes. The tie plate can furthermore bedesigned as a tube-shaped support along the whole of the inside of thepost.

FIGS. 1-5 show supports for the connection between a flange 1 and thebase of a post 3.

FIGS. 6-9 show supports for mounting a post set in a foundation.

FIG. 10 shows a support device with perforated tie plate.

FIG. 11 shows an expanded support (as in FIG. 10).

FIG. 12 shows a friction attachment at the foundation.

FIG. 1 shows supports 2 fabricated from steel straps which are thenwelded to the inside of the casing at their upper ends and to theunderside of the flange at their lower ends. The support is formed witha special bend 4, in accordance with the concept of the invention. FIG.1a shows an individual support 2. FIG. 1b shows a support mounted on theflange 1 and FIG. 1c shows six supports mounted in a post.

FIGS. 2-4 show variations of the shaping of supports in the form of ironrods, fastened at one end to the inside of the casing and at the otherin special holes in the flange.

FIG. 5 shows a variation consisting of a relatively thin tube 5 which ispressed together in its axial direction as a bellows 6. It is thenfastened to the inside of the casing and to the flange. Itsenergy-absorbing capacity is based on stretching of the tube in itsaxial direction.

FIG. 6 shows the same type of support as in FIG. 1. The post is,however, not provided with a flange, but is intended for bedding in afoundation. The supports are therefore fastened to a section 3 aboveground on the casing, and a section 7 below the ground, and are bent inone or more curves between these sections.

FIGS. 7-8 show designs corresponding to FIG. 6, but using rod supports.

FIG. 9 shows the same design as in FIG. 5, but with a compressed,slotted tube fastened to a section above ground and to a section belowground. The tube is formed with support arms 8 having special bends 9.

FIG. 10 shows a support device with tie plate 10 and rows of holes 11which have the last hole omitted alternately. This provides a greateramount of material 12 at those points. The rows of holes can be replacedby slots.

FIG. 11 shows a support which has been stretched as the result of anaccident. The material 13 between the rows of holes has ruptured, exceptat point 12 where the material was more solid. The tie plate has beenstretched and constitutes an energy-absorbing anchor between thefoundation and the casing of the post.

FIG. 12 shows an example of a post support with a continuous casingextending to the bottom of the foundation. The casing 3 of the post isslightly tapered and when stretched, an interaction occurs between theflange 1 and a core 14 set in the foundation.

The designs shown here are by no means the only ones satisfying theconcept of the invention. Variations can be made, for example, thesupports can be located on the outside of the casing, they can befastened by screw connections so that an energy-absorbing effect isobtained by means of friction, or they can be provided with some sort ofsprings dimensioned for the purpose.

We claim:
 1. A yieldable assembly comprising a flange, a post extending upwardly from said flange, elongated support means fixed to said flange and said post, said support means being yieldable to allow said post to separate from said flange upon being struck, for example, by a vehicle, said support means being formed to yield under tensile strain thereby serving to retain connection between said post and said flange after separation therebetween, and serving to impart a balanced restraining force to said vehicle after separation.
 2. An assembly as claimed in claim 1, said support means including a plurality of metal straps joined at opposite ends to said post and flange, said straps having an intermediate portion formed with a bend extending laterally of said post.
 3. An assembly as claimed in claim 1, said support means being metallic and fixed at opposite ends to said post and said flange and having an intermediate portion bent or deformed laterally of said post.
 4. An assembly as claimed in claim 1, said support means being formed with one or more specifically designed deformations which tend to be straightened when tension forces are applied lengthwise of said support means, thereby providing an energy absorbing attachment between said post and said flange. 